The Republicans who control state legislatures throughout the region say such laws are needed to prevent voter fraud. But such fraud is extremely rare, and Democrats are concerned that the proposed changes will make it harder for many poor voters and members of minorities — who tend to vote Democratic — to cast their ballots in states that once discriminated against black voters with poll taxes and literacy tests.

The Supreme Court ruling last month freed a number of states with a history of discrimination, mostly in the South, of the requirement to get advance federal permission in order to make changes to their election laws.

Within hours, Texas officials said that they would begin enforcing a strict photo identification requirement for voters, which had been blocked by a federal court on the ground that it would disproportionately affect black and Hispanic voters. In Mississippi and Alabama, which had passed their own voter identification laws but had not received federal approval for them, state officials said that they were moving to begin enforcing the laws.

The next flash point over voting laws will most likely be in North Carolina, where several voting bills had languished there this year as the Republicans who control the Legislature awaited the Supreme Court ruling on the Voting Rights Act of 1965, which had covered many counties in the state. After the ruling, some Republican lawmakers said that they would move as soon as next week to pass a bill requiring voters to present photo identification at the polls. And some Republicans there are considering cutting back on the number of early voting days in the state, which were especially popular among Democrats and black voters during the 2012 presidential election.

Voting laws emerged as a flash point in the 2012 presidential election after many states — including some that were not subject to special scrutiny under the Voting Rights Act — passed laws requiring voters to show photo identification, reducing early voting and making registration more difficult. Many of those new state laws were blocked, at least for that election, in state or federal courts.

Wendy R. Weiser, the director of the Democracy Program at the Brennan Center for Justice, which has challenged a number of the new voting laws in court, said the actions that states have taken since the Supreme Court ruling highlighted the need for Congress to determine which states should be covered by the Voting Rights Act in the future.

“The speed with which some of these jurisdictions have rushed forward to implement voting changes that were previously thought to be discriminatory, or at least suspected of being discriminatory, shows the real urgency for Congress acting,” she said.

But states freed from the need to win advance federal approval of new election laws can still have their laws challenged in state or federal court. Several election lawyers and voting law experts said in interviews that they expected one result of the Supreme Court ruling would be an increase in lawsuits in states that were no longer covered under the Voting Rights Act.

The Republicans who control the state government in Texas passed what some called the strictest photo identification law in the country in 2011. The law said that voters could present forms of identification that included driver’s licenses, military identification cards, passports and concealed handgun licenses, but not identification cards issued by colleges or employers. But since Texas was covered under the Voting Rights Act, the state was required to win advance approval from either the Justice Department or from a panel of judges in Washington.

A three-judge panel in Washington blocked the Texas law last year on the ground that it “imposes strict, unforgiving burdens on the poor, and racial minorities in Texas are disproportionately likely to live in poverty.”

Then, last month, the Supreme Court struck down the part of the Voting Rights Act determining which states should get extra scrutiny. The Supreme Court then vacated the earlier decision blocking the photo identification law, and state officials announced they would enforce it.

“The U.S. Supreme Court’s ruling eliminates all of the lower court’s rulings and the findings made by the lower court against the State of Texas,” the state’s attorney general, Greg Abbott, said in a statement. “The Texas voter ID law can go into effect.”

But a new lawsuit challenging the photo identification law was filed within days in Federal District Court in Corpus Christi on behalf of a group of black and Hispanic Texans, including Representative Marc Veasey, a Democrat; a veteran who lacks valid identification; and a woman whose name on her driver’s license does not match the name on her voter registration certificate.

Chad W. Dunn, a Texas elections lawyer who filed the suit, said, “Not more than two hours after the Supreme Court handed down its decision, the State of Texas went forward with implementing a photo ID law that it knew had been found to be discriminatory.”

Officials in the states that are no longer covered by the law praised the court’s ruling, saying that it had been unfair — and needlessly expensive — to single them out for special scrutiny. Gov. Rick Perry of Texas said in a statement that “Texas may now implement the will of the people without being subject to outdated and unnecessary oversight and the overreach of federal power.”

Alabama, which paved the way for the passage of the Voting Rights Act nearly a half century ago after the attack on civil rights marchers in Selma, also sparked the Supreme Court decision striking down its core provision after Shelby County, in central Alabama, challenged the law in court. The state attorney general, Luther Strange, praised the Supreme Court for recognizing “that Alabama and other covered jurisdictions could not be treated unequally based on things that happened decades ago.”

But voting rights advocates said that many changes that have been sought over the years, particularly at the local level, were anything but routine — saying that proposals to move to the at-large elections of local officials, or to annex or merge municipalities, or move or eliminate polling locations often threatened to dilute the power of minority voters.

Ms. Weiser, of the Brennan Center, said that the place where the requirements in the Voting Rights Act had prevented the most discriminatory changes had been at the local level — and that without the requirement to seek approval for such changes from Washington, many changes might be enacted now without attracting much outside notice.

“Municipal elections, school board districts — those kinds of changes don’t get the same public attention, but they really impact people where they live,” she said.

A version of this article appears in print on , Section A, Page 9 of the New York edition with the headline: After Ruling, States Rush To Enact Voting Laws. Order Reprints | Today’s Paper | Subscribe